Tow hitches are commonly used for towing one vehicle behind another. Such an assembly generally comprises a tow ball that is secured to the rear of a towing vehicle and a coupler or receiver for the tow ball that is attached to the trailer or vehicle to be towed.
Multi-ball tow hitches are disclosed in U.S. Pat. Nos. 3,922,006, 4,280,713, 4,248,450 and 5,839,744, and in U.S. Design Pat. No. 356,764. These tow hitches employ a four-sided tubular ball mount and multiple tow balls of different sizes that are welded to a side wall of the ball mount or attached by a threaded shank and nut.
Another tow hitch is disclosed in U.S. Pat. No. 7,044,494. In this hitch, different size balls are welded to respective side surfaces of a four-sided solid shank. The solid shank was considered necessary to satisfying higher capacity requirements, such as a ball/pintle capacity of at least 10,000 pounds in the tow hitch shown in the '494 patent. The solid shank contributed a substantial part of the overall weight of the tow hitch.